Doorbell push button



FIG. 1 is a cross-sectional view thereof as taken from line 1—1 of FIG. 2;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof; and,

FIG. 4 is a right front perspective view thereof. 

The ornamental design for a doorbell push button, as shown. 